CN114598331A - Polar code encoding method, encoding and decoding method and device - Google Patents

Abstract

The application discloses a Polar code encoding method, a Polar code compiling method and a Polar code compiling device. The encoding method comprises the following steps: acquiring a target code length; performing code length decomposition on the target code length to obtain a plurality of sub-code lengths; respectively carrying out channel estimation on a plurality of sub-code lengths to obtain a bit sequence; constructing a sequence group to be coded according to the bit sequence; carrying out parallel coding on the sequence group to be coded to obtain Polar codes with the target code length; wherein, each subcode length is 2ⁿA byte. The Polar coding and decoding method solves the problem that the standard Polar code cannot carry out non-2 codingⁿThe data coding with the byte length cannot be applied to the low-voltage power line, the coding flexibility of Polar codes is enhanced, and compared with the traditional coding method of the low-voltage power line, the complexity is lower, and the transmission speed of the low-voltage power line is accelerated.

Description

Polar code encoding method, encoding and decoding method and device

technical field

The present application relates to the field of communication technologies, and in particular, to a Polar code encoding method, encoding and decoding method, and apparatus.

Background technique

Power Line Communication (PLC) technology has the excellent characteristics of high transmission rate, wide transmission range, and no need to re-wire the development trend of modern communication systems. It is one of the communication methods with great potential in the application of intelligent systems. However, the power line channel is not an ideal communication channel and requires excellent reliability optimization methods. Channel coding is one of the important components in communication systems. Shannon proposed in the noisy channel coding theorem that there is a channel coding method that can achieve an arbitrarily small error probability when the information transmission rate does not exceed the channel capacity. This achievable channel capacity is also called the Shannon limit, which determines the maximum transmission rate for information transmission. However, Shannon's theorem does not point out a specific channel coding scheme for implementing Shannon's theorem. Until 2008, Professor Erdal Arikan first proposed the concept of channel polarization (Channel Polarization) at the International Information Theory ISIT Conference and proposed a new type of channel coding, Polar code, based on this concept. Polar codes have been proved to be able to strictly reach the Shannon limit under Binary Discrete Memoryless Channel (B-DMC) and Binary Erasure Channel (BEC), which is impossible for all known channel codes before. Therefore, the Polar code has attracted much attention as soon as it was proposed. In 2016, at the 3GPP RAN1#87 meeting, 3GPP, the International Organization for Mobile Communication Standardization, finally determined that the control channel coding scheme for the 5G eMBB (enhanced Mobile Broadband) scenario is Polar code.

In the power line communication system under the low-voltage power line broadband carrier communication standard specification, the physical layer receives the input data from the data link layer. The data format is divided into frame control data and payload data, which are encoded separately at the physical layer sending end. The channel encoding method is Turbo code. The frame control symbol coding block length is 16 bytes, and the code rate is 0.5. The payload symbol encoding block length supports four modes: 72 bytes, 136 bytes, 264 bytes and 520 bytes. Referring to the standard Polar code encoding and decoding method, it is necessary to iteratively combine N independent binary discrete memoryless channels that are equal to and uncorrelated with the Polar code code length through the Polar code encoding linear transformation matrix constructed from the fundamental matrix. , and then the linear transformation of the combined N independent binary discrete memoryless channels is combined into a whole vector channel through the linear transformation matrix encoded by the Polar code. This process is called channel union. The channel combing process starts from a single channel, and the number of channels doubles as the number of iterations increases, that is, the number of iterations n is related to the number of channels, that is, the data code length N, N=2 ⁿ , n≥0, so the Polar coding principle determines the standard Polar The code can only realize ²ⁿ code length encoding. After the channel union is completed, the joint channel is split again, that is, the vector channel combined by N independent binary discrete memoryless channels is split into N binary input channels that are mutually influencing and independent according to the channel transition probability, so that the split The transmission efficiency of the divided binary input channel is maximized, and the polarization of the channel is realized. The encoding and decoding method of the standard Polar code can only realize the encoding and decoding of data blocks with a code length of 2 ⁿ . In actual power line communication, the physical block length is not 2 ⁿ . Therefore, the encoding and decoding method of the standard Polar code cannot be applied to power lines. communication.

SUMMARY OF THE INVENTION

The purpose of the embodiments of the present application is to provide a Polar code encoding method, encoding and decoding method and apparatus, so as to solve the problem that the standard Polar code encoding and decoding method in the prior art cannot be applied to power line communication.

In order to achieve the above purpose, a first aspect of the present application provides a Polar code encoding method, which is applied to a low-voltage power line, and the encoding method includes:

Get the target code length;

Perform code length disassembly on the target code length to obtain multiple sub-code lengths;

Perform channel estimation on multiple subcode lengths respectively to obtain a bit sequence;

Construct the sequence group to be encoded according to the bit sequence;

Perform parallel encoding on the sequence group to be encoded to obtain the Polar encoding of the target code length;

The length of each subcode is 2 ⁿ bytes.

In the embodiment of the present application, the code length disassembly is performed on the target code length to obtain multiple sub-code lengths including:

When the target code length is less than the first threshold, disassemble the target code length into a first number of sub-code lengths;

In the case that the target code length is greater than the first threshold and less than the second threshold, decomposing the target code length into a second number of sub-code lengths;

When the target code length is greater than the second threshold, the target code length is decomposed into a third number of sub-code lengths.

In the embodiment of the present application, channel estimation is performed on multiple subcode lengths respectively to obtain a bit sequence including:

Perform channel estimation on polarized subchannels corresponding to multiple subcode lengths;

Combine the polarized sub-channels to obtain the overall reliability sequence;

Sort the overall reliability sequence in descending order to get the first order;

Screen the sequence numbers of the target lengths to be encoded according to the first order to obtain the bit sequence.

In this embodiment of the present application, the channel estimation is Gaussian estimation.

In the embodiment of the present application, constructing the sequence group to be encoded according to the bit sequence includes:

Using the first preset number of information bits as cyclic redundancy check transmission bits;

using the second preset number of information bits as data bit transmission bits;

Using the third preset number of transmission bits as a frozen bit sequence;

Determine the sequence to be encoded according to the cyclic redundancy check transmission bit, the data bit transmission bit and the frozen bit sequence;

Split the sequence to be encoded into corresponding positions in the polar code group according to the categories of multiple subcode lengths to obtain the sequence group to be encoded;

Wherein, the sum of the first preset number and the second preset number is the target length to be encoded; the sum of the target length to be encoded and the third preset number is the target code length; the reliability of the data bit transmission bit is greater than the CRC The reliability of the transmitted bits is checked; the reliability of the cyclic redundancy check transmission bits is greater than that of the frozen bit sequence.

In the embodiment of the present application, the parallel encoding of the sequence group to be encoded to obtain the Polar encoding of the target code length includes:

According to the number of subcode lengths, parallel coding is performed on the sequence group to be coded to obtain multiple sets of Polar codes;

Combine multiple sets of Polar codes to obtain a Polar code with a target code length.

In the embodiment of the present application, parallel coding is performed on the sequence group to be coded according to the number of subcode lengths to obtain multiple sets of Polar codes including:

Determine the number of encoders according to the number of subcode lengths;

Input the sequence to be encoded into the corresponding encoder according to the subcode length category;

The sequence group to be encoded is encoded in parallel by multiple encoders to obtain multiple groups of Polar encoding.

A second aspect of the present application provides a Polar code encoding and decoding method, which is applied to a low-voltage power line, and the encoding and decoding method includes:

The encoding method of the above-mentioned Polar code;

Perform parallel decoding on the Polar code of the target code length to obtain multiple sets of target decoding results;

Multiple sets of target decoding results are combined by path selection to obtain the final decoding result.

In this embodiment of the present application, performing path selection and merging on multiple sets of target decoding results to obtain a final decoding result includes:

Select a target decoding path from each group of target decoding results to perform path combination;

Determine the path metrics for each path combination and sort to get the second order;

Perform cyclic redundancy checks in sequence according to the second order;

The first path combination that passes the cyclic redundancy check is determined as the final decoding result.

A third aspect of the present application provides a polar code encoding and decoding device, which is applied to a low-voltage power line, including:

a memory configured to store the instructions; and

The processor is configured to call the instruction from the memory, and when executing the instruction, can implement the above-mentioned encoding method of Polar code or the above-mentioned method of encoding and decoding Polar code.

A fourth aspect of the present application provides a machine-readable storage medium, where instructions are stored on the machine-readable storage medium, and the instructions are used to cause a machine to execute the above-mentioned Polar code encoding method or the above-mentioned Polar code encoding and decoding method.

Through the above technical solution, in the low-voltage power line, the obtained target code length is subjected to code length disassembly to obtain multiple sub-code lengths, wherein each sub-code length is 2 ⁿ bytes; Channel estimation is performed to obtain a bit sequence; then a sequence group to be coded is constructed according to the bit sequence; parallel coding is performed on the sequence group to be coded to obtain the Polar coding of the target code length. The Polar encoding method of the present application solves the problem that the standard Polar code cannot encode data with a length of non-2 ⁿ bytes, and thus cannot be applied to low-voltage power lines, enhances the coding flexibility of the Polar code, and is more flexible than traditional low-voltage power lines. The encoding method is less complex and speeds up transmission over low-voltage power lines.

Other features and advantages of the embodiments of the present application will be described in detail in the detailed description section that follows.

Description of drawings

The accompanying drawings are used to provide further understanding of the embodiments of the present application, and constitute a part of the specification, and are used to explain the embodiments of the present application together with the following specific embodiments, but do not constitute limitations to the embodiments of the present application. In the attached image:

FIG. 1 schematically shows a schematic flowchart of a method for encoding a Polar code according to an embodiment of the present application;

FIG. 2 schematically shows a schematic flowchart of code length disassembly for a target code length according to an embodiment of the present application;

FIG. 3 schematically shows a schematic flowchart of a method for encoding and decoding a Polar code according to an embodiment of the present application;

FIG. 4 schematically shows a schematic diagram of an application environment of a Polar code encoding and decoding method according to a specific embodiment of the present application;

FIG. 5 schematically shows a structural block diagram of an apparatus for encoding and decoding a Polar code according to an embodiment of the present application.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. It should be understood that the The specific embodiments described are only used to illustrate and explain the embodiments of the present application, and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present application.

It should be noted that if there are directional indications (such as up, down, left, right, front, back, etc.) involved in the embodiments of the present application, the directional indications are only used to explain a certain posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly.

In addition, if there are descriptions related to "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only for the purpose of description, and should not be construed as indicating or implying Its relative importance or implicitly indicates the number of technical features indicated. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In addition, the technical solutions between the various embodiments can be combined with each other, but must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of such technical solutions does not exist. , is not within the scope of protection claimed in this application.

FIG. 1 schematically shows a schematic flowchart of a method for encoding a Polar code according to an embodiment of the present application. As shown in FIG. 1 , an embodiment of the present application provides an encoding method for a Polar code, which is applied to a low-voltage power line, and the encoding method may include the following steps:

Step 101, obtaining the target code length;

Step 102, performing code length disassembly on the target code length to obtain multiple sub-code lengths;

Step 103: Perform channel estimation on multiple subcode lengths respectively to obtain a bit sequence;

Step 104, construct the sequence group to be encoded according to the bit sequence;

Step 105, performing parallel encoding on the sequence group to be encoded to obtain the Polar encoding of the target code length;

The length of each subcode is 2 ⁿ bytes.

The encoding method of the Polar code according to the embodiment of the present application is applied to a low-voltage power line. The power line communication system under the low-voltage power line broadband carrier communication standard specification, the payload symbol coding block length supports four modes: 72 bytes, 136 bytes, 264 bytes and 520 bytes. In the embodiment of the present application, the channel coding method of the low-voltage power line is reselected as the Polar code. The capacity of the Polar code is up to the code and there is no error-free leveling, and the coding and decoding complexity is low, so that the channel coding maintains the superior performance similar to that of the Turbo code. Reduce the complexity of channel coding and decoding.

In the embodiment of the present application, the code length disassembly refers to disassembling the target code length into a set of sub code lengths, each of which is 2 ⁿ bytes. In the low-voltage power system, the target length K to be encoded can be 72 bytes, 136 bytes, 264 bytes and 520 bytes. Since the code rate is 0.5, the target code length N can be 144 bytes, 272 bytes, 528 bytes and 1040 bytes. For code length disassembly, the target code length can be disassembled into multiple parts, wherein the first part can be 2 ⁴ =16 bytes, and the rest can also be disassembled into multiple 2 ⁿ bytes. For example, for 144 bytes, it can be split into 16 bytes and 128 bytes, which are ²⁴ bytes and ²⁷ bytes respectively; for 272 bytes, it can be split into 16 bytes and 256 bytes. , respectively 2 ⁴ bytes and 2 ⁸ bytes; for 528 bytes, it can be split into 16 bytes and two 256 bytes, respectively 2 ⁴ bytes and two 2 ⁸ bytes; for 1040 bytes Can be split into 16 bytes and four 256 bytes, 2 ⁴ bytes and four 2 ⁸ bytes respectively. In this way, the non-standard code length is disassembled into multiple sub-code lengths of 2 ⁿ bytes, balancing resource consumption and encoding and decoding performance, and realizing the Polar encoding of the target code length of non-2 ⁿ bytes, which is the parallel encoding and Parallel decoding lays the foundation.

After the target code length is disassembled and multiple subcode lengths are obtained, channel polarization is performed on the grouping results of the multiple subcode lengths, and the channel estimates the reliability of the corresponding channel transmission. Then the reliability sets of the packets are combined, and the overall reliability sets are arranged in descending order, and then the sequence numbers of the K channels with the highest reliability are screened to form the bit sequence of the overall information. Taking the target code length N as 144 bytes as an example, N ₁ and N ₂ correspond to 16 and 128 bytes respectively, and each byte corresponds to one channel. After estimating the reliability of each channel _of N1 and _N2 separately, the two sets of reliability are combined and merged. The overall reliability sequence is arranged in descending order, that is, according to the sequence number 1 to the sequence number 144, to obtain the channels corresponding to 144 bytes whose reliability is arranged in descending order. The sequence numbers of the K channels with the highest reliability are screened, that is, the 72 sequence numbers with the highest reliability, and these 72 sequence numbers can constitute an overall information bit sequence. Preferably, the channel estimation in the embodiment of the present application may select Gaussian estimation, and the reliability result obtained by using the Gaussian estimation is more accurate.

After the bit sequence is obtained, a sequence group to be encoded can be constructed according to the bit sequence. When selecting information bits, multiple subcode lengths can be considered as a whole. The error probability is calculated for each sub-channel corresponding to each sub-code length, the error probability of all channels is sorted and selected, and these information bits are scattered in each code block. For a single polar code, the code rate is not necessarily the target code rate, but for the entire polar code, the code rate is the target code rate. In this embodiment of the present application, the bit sequence can be processed in two parts, the 2 bytes with the worst reliability are used as cyclic redundancy check (Cyclic Redundancy Check, CRC) transmission bits, and the remaining information bits can be transmitted as data bits bits, and the remaining transmission bits outside the bit sequence can be frozen bit sequences, filled with 0 bits. According to the above-mentioned cyclic redundancy check transmission bits, data bit transmission bits and frozen bit sequences, the sequence to be encoded can be determined, and then the sequence to be encoded can be divided into corresponding positions in the polar code group according to the categories of multiple subcode lengths, so as to obtain the sequence to be encoded. sequence group. Taking a bit sequence including 72 serial numbers as an example, the corresponding target code length is 144 bytes. The 2 bytes with the worst reliability are used as the CRC transmission bits, the remaining 70 bytes are used as the data bit transmission bits, and the remaining 72 transmission bits are the frozen bit sequence, which can constitute the sequence to be encoded. For 144 bytes, it is disassembled into two parts, 16 bytes and 128 bytes, and the to-be-encoded sequence is classified according to 16-byte and 128-byte to obtain 16-byte and 128-byte to-be-encoded sequence groups.

After the sequence group to be coded is obtained, the sequence group to be coded can be coded in parallel according to the number of subcode lengths, and the generator matrix is calculated in turn to obtain multiple sets of Polar codes; and then multiple sets of Polar codes are combined to obtain the target code length. Polar code. In an example, the to-be-coded sequence may be input to the corresponding encoder according to the subcode length category, and then the to-be-coded sequence group is encoded in parallel by multiple encoders. Taking the target length K=72 bytes to be encoded as an example, the target code length of 144 bytes is divided into 16 bytes and 128 bytes of sequence groups to be encoded. 16 bytes pass through Polar encoder 1, and 128 bytes pass through Polar encoder 2, respectively, to obtain two sets of encoded Polar codes. Then splicing the two sets of Polar codes in sequence, for example, splicing 16 bytes first, and then 144 bytes in sequence, so as to obtain an encoded sequence of 144 bytes, that is, the Polar code with the target code length.

Through the above technical solution, in the low-voltage power line, the obtained target code length is subjected to code length disassembly to obtain multiple sub-code lengths, wherein each sub-code length is 2 ⁿ bytes; Channel estimation is performed to obtain a bit sequence; then a sequence group to be coded is constructed according to the bit sequence; parallel coding is performed on the sequence group to be coded to obtain the Polar coding of the target code length. The above-mentioned Polar coding method solves the problem that the standard Polar code cannot encode data with a length other than 2 ⁿ bytes, so it cannot be applied to low-voltage power lines, and enhances the coding flexibility of the Polar code. Compared with traditional low-voltage power line coding The method complexity is lower.

In this embodiment of the present application, step 102, performing code length disassembly on the target code length to obtain multiple sub-code lengths may include:

When the target code length is less than the first threshold, disassemble the target code length into a first number of sub-code lengths;

In the case that the target code length is greater than the first threshold and less than the second threshold, decomposing the target code length into a second number of sub-code lengths;

When the target code length is greater than the second threshold, the target code length is decomposed into a third number of sub-code lengths.

Specifically, in the low-voltage power system, the target length K to be encoded can be 72 bytes, 136 bytes, 264 bytes and 520 bytes. Since the code rate is 0.5, the target code length N can be 144 bytes, 272 bytes bytes, 528 bytes, and 1040 bytes. For code length disassembly, the target code length can be disassembled into multiple parts, wherein the first part can be 2 ⁴ =16 bytes, and the rest can also be disassembled into multiple 2 ⁿ bytes.

FIG. 2 schematically shows a schematic flowchart of code length disassembly for a target code length according to an embodiment of the present application. As shown in FIG. 2 , in this embodiment of the present application, two thresholds may be set, for example, the first threshold may be 512 bytes, and the second threshold may be 1024 bytes. Therefore, code length disassembly can be divided into three cases. Case 1: When the input code length N is less than 512 bytes, the target code length may be 144 bytes or 272 bytes, and the target code length can be disassembled into two parts, namely j=2, respectively N ₁ =16 bytes, N ₂ =NN ₁ . For example, when the target code length is 144 bytes, N ₁ =16 bytes, N ₂ =128 bytes; when the target code length is 272 bytes, N ₁ =16 bytes, N ₂ = 256 bytes. Case 2: When the input code length N is greater than 512 bytes and less than 1024 bytes, the target code length is 528 bytes, and the target code length can be disassembled into three parts, namely j=3, respectively N ₁ =16 bytes, N ₂ =N ₃ =256 bytes. Case 3: When the input code length N is greater than 1024 bytes, that is, the target code length is 1040 bytes, the target code length can be disassembled into five parts, namely j=5, respectively N ₁ =16 bytes, N ₂ =N3 _{= N4} = _N5 =256 bytes. In this way, the non-standard code length is disassembled into multiple sub-code lengths of 2 ⁿ bytes, balancing resource consumption and encoding and decoding performance, and realizing the Polar encoding of the target code length of non-2 ⁿ bytes, which is the parallel encoding and Parallel decoding lays the foundation.

In this embodiment of the present application, in step 103, channel estimation is performed on a plurality of subcode lengths respectively to obtain a bit sequence, which may include:

Perform channel estimation on polarized subchannels corresponding to multiple subcode lengths;

Combine the polarized sub-channels to obtain the overall reliability sequence;

Sort the overall reliability sequence in descending order to get the first order;

Screen the sequence numbers of the target lengths to be encoded according to the first order to obtain the bit sequence.

Specifically, taking the target code length N of 144 bytes as an example, N ₁ and N ₂ correspond to 16 and 128 bytes respectively, and each byte corresponds to one channel. After estimating the reliability of each channel _of N1 and _N2 separately, the two sets of reliability are combined and merged. Arrange the overall reliability sequence from largest to smallest to get the first order. The first order includes channels corresponding to 144 bytes whose reliability is arranged in descending order, and is sorted according to the sequence number 1 to the sequence number 144. The sequence numbers of the K channels with the highest reliability are screened, that is, the 72 sequence numbers with the highest reliability, and these 72 sequence numbers can constitute an overall information bit sequence.

In this embodiment of the present application, the channel estimation may be Gaussian estimation.

Specifically, the operation steps of Gaussian estimation are as follows:

1. First input parameters: target code length N, code rate R and noise variance σ;

2. Recursively calculate each channel parameter m according to the following steps:

iv. where the function:

3. The probability that the variable node is wrongly judged is

4. Select the sequence numbers of the smallest K=NR values in the P sequence, and arrange them in descending order of reliability to generate an information bit sequence p.

The channel estimation in the embodiment of the present application adopts Gaussian estimation to obtain a more accurate reliability result.

In this embodiment of the present application, in step 104, constructing a sequence group to be encoded according to the bit sequence may include:

Using the first preset number of information bits as cyclic redundancy check transmission bits;

using the second preset number of information bits as data bit transmission bits;

Using the third preset number of transmission bits as a frozen bit sequence;

Determine the sequence to be encoded according to the cyclic redundancy check transmission bit, the data bit transmission bit and the frozen bit sequence;

Split the sequence to be encoded into corresponding positions in the polar code group according to the categories of multiple subcode lengths to obtain the sequence group to be encoded;

Wherein, the sum of the first preset number and the second preset number is the target length to be encoded; the sum of the target length to be encoded and the third preset number is the target code length; the reliability of the data bit transmission bit is greater than that of the CRC The reliability of the transmitted bits is checked; the reliability of the cyclic redundancy check transmission bits is greater than that of the frozen bit sequence.

Specifically, in the embodiment of the present application, the bit sequence may be processed in two parts, and the first preset number (for example, 2 bytes) with the worst reliability is transmitted as a cyclic redundancy check (Cyclic Redundancy Check, CRC). bits, the remaining second preset number of information bits may be used as data bit transmission bits, and the third preset number of remaining transmission bits other than the bit sequence may be frozen bit sequences filled with 0 bits. Therefore, in the sequence to be encoded, the reliability of the data bit transmission bit is the best, the reliability of the cyclic redundancy check transmission bit is second, and the reliability of the frozen bit sequence is the worst. According to the above-mentioned cyclic redundancy check transmission bits, data bit transmission bits and frozen bit sequences, the sequence to be encoded can be determined, and then the sequence to be encoded can be divided into corresponding positions in the polar code group according to the categories of multiple subcode lengths to obtain the sequence to be encoded. sequence group. Taking a bit sequence including 72 serial numbers as an example, the corresponding target code length is 144 bytes. The first preset number is 2, the second preset number is 72-2=70 bytes, and the third preset number is 144-72=72 bytes. Therefore, the 2 bytes with the worst reliability can be used as the CRC transmission bits, the remaining 70 bytes can be used as the data bit transmission bits, and the remaining 72 transmission bits are the frozen bit sequence, which can constitute the to-be-encoded sequence. For 144 bytes, it is disassembled into two parts, 16 bytes and 128 bytes, and the to-be-encoded sequence is classified according to 16-byte and 128-byte to obtain 16-byte and 128-byte to-be-encoded sequence groups.

In the embodiment of the present application, step 105, performing parallel coding on the sequence group to be coded to obtain the Polar coding of the target code length may include:

According to the number of subcode lengths, parallel coding is performed on the sequence group to be coded to obtain multiple sets of Polar codes;

Combine multiple sets of Polar codes to obtain a Polar code with a target code length.

Specifically, after obtaining the sequence group to be coded, the sequence group to be coded can be encoded in parallel according to the number of subcode lengths, and the generator matrix can be calculated in turn to obtain multiple sets of Polar codes; and then the multiple sets of Polar codes can be combined to obtain the target Code length Polar encoding.

In this embodiment of the present application, the Polar encoding may include the following steps:

1. Preset initialization matrix

其中n分别为拆解模块的码长N_i对应的幂次n_i，

代表克罗内克积计算；2. Calculation

where n is the power n _i corresponding to the code length N _i of the dismantling module, respectively,

represents the Kronecker product calculation;

3. Perform reverse order rearrangement mapping on the coding sequence, the specific steps are as follows:

i. Index the original sequence to -1;

ii. Convert the sequence index from decimal to binary;

iii. Reverse the original binary index;

iv. Convert the sequence index from binary to decimal;

v.index value+1;

vi. Change the information bits corresponding to the original index value of the sequence to be encoded to the new index value to obtain the rearranged sequence in reverse order of bits

4. Coding sequence

In the embodiment of the present application, performing parallel coding on the sequence group to be coded according to the number of subcode lengths to obtain multiple sets of Polar codes may include:

Determine the number of encoders according to the number of subcode lengths;

Input the sequence to be encoded into the corresponding encoder according to the subcode length category;

The sequence group to be encoded is encoded in parallel by multiple encoders to obtain multiple groups of Polar encoding.

Specifically, the number of encoders can be determined first. For example, the target code length is 144 bytes, and after being split, 16-byte and 128-byte sequence groups to be encoded can be obtained, so the corresponding encoders are two encoders. The to-be-coded sequence can be input to the corresponding encoder according to the subcode length category, and then the to-be-coded sequence group is encoded in parallel by multiple encoders. Still taking the target length K=72 bytes to be encoded as an example, the target code length of 144 bytes is divided into 16 bytes and 128 bytes of sequence groups to be encoded. 16 bytes pass through Polar encoder 1, and 128 bytes pass through Polar encoder 2, respectively, to obtain two sets of encoded Polar codes. Then splicing the two sets of Polar codes in sequence, for example, splicing 16 bytes first, and then 144 bytes in sequence, so as to obtain an encoded sequence of 144 bytes, that is, the Polar code with the target code length. By parallel encoding, the parallelism of Polar code encoding can be enhanced.

FIG. 3 schematically shows a schematic flowchart of a method for encoding and decoding a Polar code according to an embodiment of the present application. As shown in FIG. 3 , an embodiment of the present application provides a Polar code encoding and decoding method, which is applied to a low-voltage power line. The encoding and decoding method may include the following steps:

The encoding method of the above-mentioned Polar code;

Step 106, carrying out parallel decoding to the Polar encoding of the target code length, to obtain multiple groups of target decoding results;

Step 107: Perform path selection and combination of multiple sets of target decoding results to obtain a final decoding result.

In this embodiment of the present application, the Polar decoder may include the following steps:

1. Path expansion. Path expansion means that the upper layer of the current path does 01 branches in turn, that is, the number of paths is expanded by 2 times after each path expansion operation;

2. Determine whether the current number of paths l is greater than the maximum number of search paths L, where L=8; if it is greater, go to step 3; otherwise, return to step 1;

3. Calculate the path metric value of each path;

4. Keep the 8 paths with the smallest path metric value, and delete the rest;

Specifically, taking the target code length of 144 bytes as an example, the length of the sequence to be decoded is 144 bytes, which is divided into two parts of 16 bytes and 128 bytes, and passes through the Polar decoder 1 and the Polar decoder in parallel. 2 decoding to obtain two sets of target decoding results with the number of paths being L=8. A combination of decoding paths is selected from each set to obtain all possible combinations of paths. Calculate and sort the path metrics for each combination. According to the sorting results from good to bad (path metric values from small to large), the CRC check is performed in sequence, and the check result of the first path combination that passes the CRC check is determined as the final decoding result. The embodiment of the present application realizes the encoding of the target code length other than 2 ⁿ bytes, and at the same time enhances the parallelism of Polar encoding and decoding, and reduces the decoding complexity to O(LN _max log ₂ N _max ), where N _max is the disassembly The maximum code length in the obtained code group effectively reduces the delay of encoding and decoding, and accelerates the transmission speed of the low-voltage power line.

In this embodiment of the present application, performing path selection and merging of multiple sets of target decoding results to obtain a final decoding result may include:

Select a target decoding path from each group of target decoding results to perform path combination;

Determine the path metrics for each path combination and sort to get the second order;

Perform cyclic redundancy checks in sequence according to the second order;

The first path combination that passes the cyclic redundancy check is determined as the final decoding result.

Specifically, the second order is the order of path metric values from small to large (that is, from good to bad paths). One decoding path combination is selected from the target decoding results of the two groups of paths whose number is L=8, and 64 possible combinations of all paths are obtained. Calculate and sort the path metrics for each combination. According to the sorting result, CRC check is performed on the combined paths from good to bad, and the first result that passes the CRC check is the final decoding result.

In the above decoding description, the 01 branch means that the decoding result of each bit has two types: 0 and 1. The path is a possibility of the decoding result. After the received sequence waiting to be decoded is split, 8 is calculated. A feasible decoding result is determined, and the final decoding result is determined according to the double judgment of the path metric value and the CRC check.

The main purpose of the embodiments of the present application is to design a polar code encoding and decoding method with a code length other than 2 ⁿ for the power line communication system encoding mode specified by the low-voltage power line broadband carrier standard. FIG. 4 schematically shows a schematic diagram of an application environment of a polar code encoding and decoding method according to a specific embodiment of the present application. As shown in FIG. 4 , in this specific embodiment, the data link layer is connected, and the input sequence is reconstructed by code length disassembly, Gaussian estimation, multiple Polar encoders, OFDM modulators, OFDM demodulators and Polar decoding. device composition. The core part of this application is the code length disassembly and sequence reconstruction module. The code length disassembly module sets two thresholds to select a specific disassembly scheme to obtain a set of ²ⁿ code length sets. The feature of the sequence reconstruction module is that the complete polar code is divided into multiple polar code blocks in the code length disassembly module, but it is regarded as a whole when selecting information bits. The error probability is calculated for each sub-channel of each polar code according to the code length and channel parameters, and the error probability of all channels is sorted and selected, and these information bits are scattered in each code block. For a single polar code, the code rate is not necessarily the target code rate, but for the entire polar code, the code rate is the target code rate. For a specific Polar code encoding and decoding method, refer to the foregoing embodiments.

FIG. 5 schematically shows a structural block diagram of an apparatus for encoding and decoding a Polar code according to an embodiment of the present application. As shown in FIG. 5 , an embodiment of the present application provides an apparatus for encoding and decoding a Polar code, which is applied to a low-voltage power line, and may include:

memory 510 configured to store instructions; and

The processor 520 is configured to call the instruction from the memory 510 and implement the above-mentioned encoding method of Polar code or the above-mentioned encoding and decoding method of Polar code when executing the instruction.

Specifically, in this embodiment of the present application, the processor 520 may be configured to:

Get the target code length;

Perform code length disassembly on the target code length to obtain multiple sub-code lengths;

Perform channel estimation on multiple subcode lengths respectively to obtain a bit sequence;

Construct the sequence group to be encoded according to the bit sequence;

Perform parallel encoding on the sequence group to be encoded to obtain the Polar encoding of the target code length;

The length of each subcode is 2 ⁿ bytes.

Further, the processor 520 can also be configured to:

Perform code length disassembly on the target code length to obtain multiple sub-code lengths including:

When the target code length is less than the first threshold, disassemble the target code length into a first number of sub-code lengths;

In the case that the target code length is greater than the first threshold and less than the second threshold, decomposing the target code length into a second number of sub-code lengths;

When the target code length is greater than the second threshold, the target code length is decomposed into a third number of sub-code lengths.

Further, the processor 520 can also be configured to:

Perform channel estimation on multiple subcode lengths respectively to obtain a bit sequence including:

Perform channel estimation on polarized subchannels corresponding to multiple subcode lengths;

Combine the polarized sub-channels to obtain the overall reliability sequence;

Sort the overall reliability sequence in descending order to get the first order;

Screen the sequence numbers of the target lengths to be encoded according to the first order to obtain the bit sequence.

In this embodiment of the present application, the channel estimation is Gaussian estimation.

Further, the processor 520 can also be configured to:

Constructing the sequence group to be encoded according to the bit sequence includes:

Using the first preset number of information bits as cyclic redundancy check transmission bits;

using the second preset number of information bits as data bit transmission bits;

Using the third preset number of transmission bits as a frozen bit sequence;

Determine the sequence to be encoded according to the cyclic redundancy check transmission bit, the data bit transmission bit and the frozen bit sequence;

Split the sequence to be encoded into corresponding positions in the polar code group according to the categories of multiple subcode lengths to obtain the sequence group to be encoded;

Wherein, the sum of the first preset number and the second preset number is the target length to be encoded; the sum of the target length to be encoded and the third preset number is the target code length; the reliability of the data bit transmission bit is greater than that of the CRC The reliability of the transmitted bits is checked; the reliability of the cyclic redundancy check transmission bits is greater than that of the frozen bit sequence.

Further, the processor 520 can also be configured to:

The parallel encoding of the sequence group to be encoded to obtain the Polar encoding of the target code length includes:

According to the number of subcode lengths, parallel coding is performed on the sequence group to be coded to obtain multiple sets of Polar codes;

Combine multiple sets of Polar codes to obtain a Polar code with a target code length.

Further, the processor 520 can also be configured to:

According to the number of subcode lengths, the sequence group to be coded is coded in parallel to obtain multiple sets of Polar codes, including:

Determine the number of encoders according to the number of subcode lengths;

Input the sequence to be encoded into the corresponding encoder according to the subcode length category;

The sequence group to be encoded is encoded in parallel by multiple encoders to obtain multiple groups of Polar encoding.

Further, the processor 520 can also be configured to:

The encoding method of the above-mentioned Polar code;

Perform parallel decoding on the Polar code of the target code length to obtain multiple sets of target decoding results;

Multiple sets of target decoding results are combined by path selection to obtain the final decoding result.

Further, the processor 520 can also be configured to:

The path selection and combination of multiple sets of target decoding results to obtain the final decoding results include:

Select a target decoding path from each group of target decoding results to perform path combination;

Determine the path metrics for each path combination and sort to get the second order;

Perform cyclic redundancy checks in sequence according to the second order;

The first path combination that passes the cyclic redundancy check is determined as the final decoding result.

Through the above technical solution, in the low-voltage power line, the obtained target code length is subjected to code length disassembly to obtain multiple sub-code lengths, wherein each sub-code length is 2 ⁿ bytes; Channel estimation is performed to obtain a bit sequence; then a sequence group to be coded is constructed according to the bit sequence; parallel coding is performed on the sequence group to be coded to obtain the Polar coding of the target code length. The Polar encoding method of the present application solves the problem that the standard Polar code cannot encode data with a length of non-2 ⁿ bytes, and thus cannot be applied to low-voltage power lines, enhances the coding flexibility of the Polar code, and is more flexible than traditional low-voltage power lines. The encoding method is less complex and speeds up transmission over low-voltage power lines.

Embodiments of the present application further provide a machine-readable storage medium, where instructions are stored on the machine-readable storage medium, and the instructions are used to cause a machine to execute the above-mentioned Polar code encoding method or the above-mentioned Polar code encoding and decoding method.

As will be appreciated by those skilled in the art, the embodiments of the present application may be provided as a method, a system, or a computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It will be understood that each process and/or block in the flowchart illustrations and/or block diagrams, and combinations of processes and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to the processor of a general purpose computer, special purpose computer, embedded processor or other programmable data processing device to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing device produce Means for implementing the functions specified in a flow or flow of a flowchart and/or a block or blocks of a block diagram.

These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory result in an article of manufacture comprising instruction means, the instructions The apparatus implements the functions specified in the flow or flow of the flowcharts and/or the block or blocks of the block diagrams.

These computer program instructions can also be loaded on a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that The instructions provide steps for implementing the functions specified in the flow or blocks of the flowcharts and/or the block or blocks of the block diagrams.

In a typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

Memory may include non-persistent memory in computer readable media, random access memory (RAM) and/or non-volatile memory in the form of, for example, read only memory (ROM) or flash memory (flash RAM). Memory is an example of a computer-readable medium.

Computer-readable media includes both persistent and non-permanent, removable and non-removable media, and storage of information can be implemented by any method or technology. Information may be computer readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), Flash Memory or other memory technology, Compact Disc Read Only Memory (CD-ROM), Digital Versatile Disc (DVD) or other optical storage, Magnetic tape cartridges, magnetic tape disk storage or other magnetic storage devices or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media, such as modulated data signals and carrier waves.

It should also be noted that the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device comprising a series of elements includes not only those elements, but also Other elements not expressly listed, or which are inherent to such a process, method, article of manufacture, or apparatus are also included. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in the process, method, article of manufacture or apparatus that includes the element.

The above are merely examples of the present application, and are not intended to limit the present application. Various modifications and variations of this application are possible for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the scope of the claims of this application.

Claims (11)

1. A Polar code coding method is applied to a low-voltage power line, and is characterized by comprising the following steps:

acquiring a target code length;

performing code length decomposition on the target code length to obtain a plurality of sub-code lengths;

respectively carrying out channel estimation on the plurality of sub-code lengths to obtain a bit sequence;

constructing a sequence group to be coded according to the bit sequence;

performing parallel coding on the sequence group to be coded to obtain Polar codes with the target code length;

wherein each subcode length is 2ⁿA byte.

2. The encoding method of claim 1, wherein the performing code length decomposition on the target code length to obtain a plurality of sub-code lengths comprises:

under the condition that the target code length is smaller than a first threshold value, the target code length is disassembled into a first number of sub-code lengths;

under the condition that the target code length is larger than the first threshold and smaller than a second threshold, the target code length is disassembled into a second number of sub-code lengths;

and under the condition that the target code length is greater than the second threshold value, the target code length is disassembled into a third number of sub-code lengths.

3. The encoding method of claim 1, wherein the performing channel estimation on the plurality of sub-code lengths to obtain the bit sequence respectively comprises:

performing channel estimation on the polarized sub-channels corresponding to the plurality of sub-code lengths;

combining the polarized sub-channels to obtain an overall reliability sequence;

sequencing the overall reliability sequence from big to small to obtain a first sequence;

and screening the serial numbers of the target length to be coded according to the first sequence to obtain the bit sequence.

4. The encoding method of claim 1, wherein the channel estimate is a gaussian estimate.

5. The encoding method according to claim 1, wherein the constructing the group of sequences to be encoded according to the bit sequence comprises:

using a first preset number of information bits as cyclic redundancy check transmission bits;

using a second preset number of information bits as data bit transmission bits;

taking a third preset number of transmission bits as a frozen bit sequence;

determining a sequence to be coded according to the cyclic redundancy check transmission bit, the data bit transmission bit and the frozen bit sequence;

splitting the sequence to be coded to the corresponding position in a polarized code group according to the category of the plurality of sub-code lengths to obtain the sequence group to be coded;

the sum of the first preset quantity and the second preset quantity is the length of a target to be coded; the sum of the target length to be coded and the third preset number is the target code length; the reliability of the data bit transmission bit is greater than the reliability of the cyclic redundancy check transmission bit; the reliability of the cyclic redundancy check transmission bit is greater than the reliability of the frozen bit sequence.

6. The encoding method according to claim 1, wherein the parallel encoding of the sequence group to be encoded to obtain the Polar code of the target code length comprises:

carrying out parallel coding on the sequence group to be coded according to the number of the sub-code lengths to obtain a plurality of groups of Polar codes;

and combining the multiple groups of Polar codes to obtain the Polar codes with the target code length.

7. The encoding method according to claim 6, wherein the parallel encoding of the sequence group to be encoded according to the number of the sub-code lengths to obtain multiple groups of Polar codes comprises:

determining the number of encoders according to the number of the sub-code lengths;

inputting the code sequence to be coded into a corresponding coder according to the category of the sub-code length;

and carrying out parallel coding on the sequence group to be coded through a plurality of coders to obtain a plurality of groups of Polar codes.

8. A Polar code coding and decoding method is applied to a low-voltage power line, and comprises the following steps:

the coding method of Polar code according to any one of claims 1 to 7;

performing parallel decoding on Polar codes with target code length to obtain a plurality of groups of target decoding results;

and carrying out path selection and combination on the multiple groups of target decoding results to obtain a final decoding result.

9. The encoding and decoding method of claim 8, wherein the performing path selection combining on the plurality of sets of target decoding results to obtain a final decoding result comprises:

respectively selecting a target decoding path from each group of target decoding results to carry out path combination;

determining and sorting the path metric values of each path combination to obtain a second order;

performing cyclic redundancy check in sequence according to the second sequence;

and determining the first path combination passing through the cyclic redundancy check as a final decoding result.

10. A Polar code coding and decoding device is applied to a low-voltage power line and is characterized by comprising:

a memory configured to store instructions; and

a processor configured to call said instructions from said memory and to enable, when executing said instructions, an encoding method of a Polar code according to any of claims 1 to 7 or a coding method of a Polar code according to any of claims 8 to 9.

11. A machine-readable storage medium having stored thereon instructions for causing a machine to perform the method of encoding Polar code according to any of claims 1 to 7 or the method of encoding and decoding Polar code according to any of claims 8 to 9.

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